The ear is made up of three sections, the outer, middle, and the inner ear. The outer ear picks up all the sounds. The sound waves enter your ear canal; it increases the pitches, and makes it easier to understand the speech. The sound vibrations then bounce off of the ear drum, and the vibrations continue their journey into the middle ear. The middle ear contains three small bones, named the ossicles. They are the things that form a bridge for the vibration off the eardrum, into the inner ear. Before safely transmitting them into the inner ear, they increase and amplify the sound. The inner ear (cochlea) houses many systems of tubes, which are filled with fluids. As the sound waves travel past the inner ear, the fluids begin to move. The fluids then set off tiny hair cells into motion. The hairs then transform the soundwaves into electrical impulses, which travel along the auditory nerve, and into the brain itself. The brain then translates the nerve impulses.

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Source: http://www.vanderbilthealth.com